The invention concerns a headlamp for motor vehicles which is equipped with a projector system adapted to produce light patterns for both dimmed or front fog light beam and for main or DRL (Daytime Running Light) light beam, wherein high light intensities are ensured in the high or DRL light beam, low light intensities in the dimmed or front fog beam, and a homogeneous distribution of luminous intensity in the high or DRL beam without influencing a fixed aperture image.
At present headlamp systems exist that are equipped with a projector imaging system, which produces two lighting functions in the headlamp, namely, a generally dimmed and a high beam.
The existing projector systems are equipped with a light source, or optionally a cooling system for a light source, a reflector, an aperture and a converging lens. For example, in document CZ302002 is described a headlamp system consisting of a light source, a reflector which reflects the light emitted by the light source, an aperture and a converging lens situated in the reflected in the reflected light beam. A light pattern of specific form is achieved by means of a movable aperture, which is situated between the light source and the converging lens and which can be switched between two extreme positions: dimmed/high beam. However, this movable aperture in the first position shades some of the light reflected by the reflector, which produces a light/dark boundary for the emerging light beam, and in the second position it shades much less of the reflected light as compared to the first position but the light must go from the reflector past the aperture and produce the high beam after passing through the converging lens. The converging lens itself is fashioned as a bifocal lens and is composed of two segments, the first segment having a higher optical power than the second segment, while the first focal point of the first segment and the first focal point of the second segment are situated near the optical axis of the headlamp system between the light source and the converging lens, while the second focal point is situated closer to the converging lens than the first focal point. The light beam emerging from the light source is focused by means of the upper part of the reflector in the space of the first focal point of the first segment of the converging lens, while the lower part of the reflector focuses the light beam in the space of the first focal point of the second segment of the converging lens.
The drawback of this design is the fact that the light is emitted from one spot and this only by one light source, which does not enable the use of multiple light sources that are situated in different parts of the projector system according to the required parameters for the photometry of the emerging beam. Moreover, the solution according to document CZ302002 does not allow the use of an immovable fixed aperture for producing both types of beam, dimmed/far.
Designs of projector imaging systems are known from documents US20120039083A1 and US20110292669A1 that make it possible to realize a dimmed and a high beam, being outfitted with an immovable aperture, and the switching between the dimmed and the high beam is accomplished by the use of a separate system of at least two LED sources for the high beam. The light reflected from one reflector goes through the aperture and produces a dimmed pattern. For the use of the high beam, a further system of LED sources is activated, situated in another first focal point of a different part of the reflector. The light reflected from this part of the reflector again goes through the focal region of the single-focus lens, but now only partly passes by the aperture. The high beam can be realized either as an independent one, only activating one system of LED source and reflector, or as a so-called merged high beam, when both systems of LED source and reflector are active, and the high beam from the lower part of the reflector is added to the already existing dimmed beam.
The drawback to these solutions is the fact that they are equipped with a single-focus or monofocal converging lens, and a reflector system with a common second focal point, where both these focal points, the first focal point of the lens and the second focal point of the upper and lower parts of the reflector, are shared and lie in proximity to the clipping edge of the aperture on the optical axis of the headlamp system. As is evident, in the case of the merged high beam, the reflected light beam from the lower part of the reflector, in conjunction with the fixed aperture and the monofocal lens, will be more shaded by the aperture and thus the quantity of transmitted light will be less, and moreover the edge of the aperture (shadow of the clipping edge of the aperture) will be imaged in this high beam, which significantly degrades both the photometric efficiency and the resulting homogeneity of the high beam. The cited documents attempt to solve this problem by the use of several light sources, by reducing the thickness of the aperture in the area of the clipping edge (shape before the edge) or by complicated shapes of the clipping edge of the aperture, all with the goal of minimizing the influence of the imaging of the aperture in the high beam. The drawback is the demanding manufacture of the aperture and only partial elimination of the undesirable effect of the imaging.
The problem of the proposed invention is to present a new headlamp system for motor vehicles operating on the projection principle, where the light is emitted from at least two light sources passing through an optical system formed by a reflector with at least two parts having a separate position for their first and second focal points and a converging lens with at least two segments having their own first focal points, and producing a dimmed or a front fog beam and a high or DRL beam, while between these light beams there is achieved a sufficient separation of the light intensity, the resulting pattern of the merged high beam and the dimmed pattern is homogeneous, and the optical efficiency is a maximum in regard to the simplicity and low manufacturing costs of the other parts of this optical system.